Kampala: Police in Uganda on Friday said they were hunting a terrorist suspect they believe is linked to Somalia`s Shebab militants and was planning an "imminent" attack in the capital Kampala.

Police spokesperson Fred Enanga said the suspect, who remains at large, had plotted to attack places popular with foreigners.

"From intelligence, they were actually targeting public places patronised by basically the whites, like some of the shopping malls," said Enanga.

"The intelligence was also talking about parks and markets within the city centre," he said.

Enanga said the suspect was "very most likely linked" to Somalia`s Shebab, an al-Qaeda affiliate responsible for double suicide bombings that killed at least 76 people in Kampala in 2010.

The United States embassy in Uganda had on Wednesday issued an emergency terror warning to its nationals.

"The US Embassy has received information of possible terrorist threats to locations where Westerners, including US citizens, congregate in Kampala, and that an attack may take place soon," the embassy said.

A similar warning was issued by the US in September, after which Ugandan security forces seized suicide vests and explosives during a raid on a suspected Shebab cell in Kampala.

Uganda is a key contributor to the African Union`s AMISOM force battling the Shebab inside Somalia, making the country a target.

Police on Friday said the single suspect had already entered the country and was being sought.

"We have the name and particulars, we are working on the identity," said Enanga.

Police chief Kale Kayihura said the threat had been "imminent".

"The threat was very specific, the attack was supposed to happen yesterday," he told reporters at a press conference at police headquarters.

Kayihura said Uganda has "foiled" numerous plots since the deadly 2010 attacks.